I've never had a new car and my current BMW is as new as any I've had when I bought it. And the original BMW branded battery died completely and without warning just outside the 3 year warranty. At the time there wasn't much of a choice for the strange shaped battery it uses - Halford for example, didn't have one. So I ended up with a Bosch which looked identical to the original apart from the name. That's still fine some 6 years on.
I assumed BMW had co-operated with Philips to produce electrical goods which die just clear of the warranty...
Open circuit voltage tells you pretty well nothing about the state of a battery. There's too much spread between samples - unless you're talking brand new. A proper tester measures the voltage while applying a heavy load. Modern ones do this using a pulse system.
The battery on my SD1 was reading 11.8 this morning - it hasn't been used for some time. But it started ok. According to that list it was completely flat.
I'd say very much an average would be 4 to 5 years with a good quality battery on a car with healthy charging system that is used regularly and allowed time to fully recharge.
That said i've seen some that are knackered or go without warning after
12-18months, but I do still have the original battery on the Volvo- its
11yrs old now, so it comes down to quality I think.
If it read 11.8 it was flat or almost so. Its voltage was pulled down artificially due to the slight evelectrical load on the car.
It inly needs a few percent left to start after all. And you would need to actually disconnect it from its loads and leave it 12 hours to see the true state af charge voltage or disconnect a battery cable the night before. Then it would climb to a stable figure and settle there. You cant measure it with a load even if its only milliamps.
Voltage DOES accurately tell you the state of charge if you do the measurement properly!. Load or pulse testing tells you its internal resistance which is a guide to its condition. Although a knakered optima will still have lower internal resistance than a new cheapy so that pulse tester isnt accurate. Plus most deep cycle batteries would fail that test from new.
Why strangely shaped? The one in my 528i is quite conventional, as was the one in a later 528i I recently sold. As long as it fits in the battery box. Has the terminals in the right place, and is not too tall for the clamp, a plain rectangular battery fits. Mike.
Which just goes to show that an unloaded voltage test is meaningless.
Not so - mine takes quite a bit of churning due to an injector leak and the fuel rail being depressurized when cold. The pump only runs when turning over.
Like I said a useless test.
That plus the current it can supply are the important things.
They are now - but not in about '99. I tried my local large factors, a good local accessory shop and Halfords - before going to Eurocarparts. Even they didn't have one but pointed me to the Bosch dealer next door.
Its still not much in terms of a percentage discharge.
No the test is and always has been valid if you know how to perform it. You failed...
You still dont seem able to get it... Voltage test = state of charge. Pulse load test = test of internal resistance (which should tell you the battery state. as in knackered or not) It has nothing to do with state of charge other than it must have enough remaining just.
Err how? They do everything claimed. They have lower internal resistance and therefore greater starting current capability than other similar weight/capacity batteries. The Deep Cycle ones also have better Current capabilities than almost any similar sized pure starter battery.
They can be fast charged in an hour with no damage at hundreds of amps provided 14.7v isnt exeeded.
Etc etc.
A con "how" ??? Because you dont understand batteries?
Sorry but they are good well made non spillable and even work upside down happily.
A small one will easily start a truck so excellent for motorsports where weight and big high compression engines are used.
Tell me mr expert, why do YOU think they are crap?
Yes but an optima deep cycle IS a car battery. It can do BOTH! They are capable of 300+ 80 percent discharges while at the same time being able to supply MORE current than a "normal" starter only battery... Even though in your expert opinion they are a con!!! After 1/5 th of that your already less capable starter battery would have shed its lead sponge coating and be nothing more than a paperweight. Which is why I will ignore your opinion since you dont have much clue about batteries.
Do you prefer the sealed maintenance free types of standard types of car battery? You mentioned yours is a deep cycle for a car? That's unusual for a car isn't it?
I'm just wondering if the sealed types don't last as long and cost more, surely they can't be better? Would love to know how the deep cycle ones for cars compare with sealed maintenance free starter ones in terms of cost.
They claim to have and actually do have the same life as any other battery thats free from defects when used under ideal conditions. They do have better performance if mistreated than other batteries but they dont actually claim that anyway.
You can even deep cycle their starter batteries to a degree with much less deterioration than a conventional starter battery due to pure thin lead rolled self supporting cells much like a ni-cad. A conventional starter battery when discharged to any major degree sheds its coating of lead sponge (used for getting a lot of area for generating big starting currents). They have to use this lead sponge to try and equal the plate area of an optima. Even so they still cannot equal the low internal resistance and so starting amps (CCA) is worse too!
You may not "need" a better battery for a healthy regularly used car so why buy one? Thats simply choice! a Normal starter battery will "work" in most cases just fine. But not all and not everybody wants an inferior cheap battery! Optimas size for size always exeed all the parameters. Reserve capacity, CCA, CA, Cycle life, electrical and physical vibtration resistance, spillability and gassing, and the most important internal eresistance.
Low internal resistance means a nominally discharged battery can a)still start a car b)charge up much faster and more efficiently without exeeding the gassing voltage of 14.7 to 14.9v In other words the voltage only goes up with the state of charge and not because you are pumping hundred amps in...
Of course many people actually DO need them apart from just knowing they have a decent battery... People that are building specials with high compression motors need the AMPS to spin them over! Especially in winter. People whose batteries have short life due to lack of use and modern cars draining the battery while sat (not to mention the lower self discharge rates of Optima AGM batteries) People with big car music systems, winches, vehicles fitted with extra equipment like my van or police, AA, etc. People that use the car only on odd occassions where the thing HAS to go (emergency vehicles, airport vehicles) Or any member of joe public that understands batteries (not you!) and wants a decent battery so he has peace of mind when he leaves his car at the airport for a month without damaging it.
In most of these cases a Yellow Top Deep Cycle battery will massively outlive a "starter" only battery as well as being able to be either smaller and lighter or the same size but bigger starting amp capability than a stock battery.
You just proved that you know nothing about batteries again.
Both have problems. Sealed have limited life due to the metals and acid strength used to stop them gassing. Standard do gas but need topping up and they leak acid.
I prefer and only use AGM (absorbed glass matt) batteries like Optima and Hawker Odyssey. Because unlike GEL batteries the occasional short or overcharge doesent cause voids in the gel increasing internal resistance and limiting starting current.
In these batteries the acid is soaked into a thin glass mat (so cant spill even if cut in half) and pure lead plates are used meaning deep cycle capability without damage. These batteries also use a clever system that remixes the oxygen and hydrogen back to water so they are totally sealed and can work even upside down...
And they dont need topping up.
Normal starter batteries use calcium/lead in lots of thin plates coated in a spongy soft lead to give a lot of surface area. (but massively thicker than optimas etc) The lead coating drops off as you use and discharge the battery and the capacity falls as well as the already lower starting current. In addition in an attempt to get as much starting amps as possible they use plates as thin as they to get more in! These warp over time and cause bad cells and then you throw the battery away.
Optimas dont need to do any of this because they are built like a capacitor. Or a nicad. The PURE lead plates are rolled up. They dont need "thickness" to have the strength to stay flat. They can roll enough pure lead up to give the more surface area than a normal battery has without needing spongy lead coating. So it cant fall off! It cant deteriorate. It can be deep cycled without damage (yellow ones deep cycle = weaker acid) or deep cycled (red ones = starter only stronger acid) with minimal damage. But since the yellow ones are already superior in starting duties compared to a normal starter battery you may as well fit a deep cycle one! Now running acessories or leaving it parked for a week or so wont do AS MUCH damage as it would with a starter only battery.
So since the optima deep cycle is a more "long lived" battery on average and because it can stand the odd heavy discharge without damage I fitted one in preferance to the red top starter only one. It has a better chance of living longer. My van has electric suspension lowering, electric door cloising, electriv ramp deployment etc. It does all this AFTER you turn the motor off.
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Yellow top fitted.
You mentioned yours is a deep cycle for a car? That's
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